1. Field of the Invention
The present invention relates to a device for locking a card in a card reader, and more particularly, to a locking mechanism included in a card reader capable of reading ID cards such as integrated circuit (IC) cards. ID cards of this type are typically compliant with ISO 7816 standards.
2. Description of the Related Art
IC cards are small plastic devices which contain one or more embedded integrated circuits for storing a user's personal data and for executing software to run business transaction applications. An IC card is programmed and the personal data is accessed with a card reader that has an aperture or slot into which the IC card is inserted. Terminals within the slot connect to terminals on the IC card to provide power and data connections for operating the IC card.
The current card readers usually use mechanical locking mechanisms to prevent the user from removing their card before a transaction is completed. These mechanisms typically employ a solenoid or DC motor to drive a linkage connected to a latch. Several problems exist in the aforesaid locking mechanisms and involve the situations when the user's card is interfering with the operation of the latch. In one case, the user may insert the IC card completely into the card reader such that the locking mechanism is activated, but is able to withdraw the IC card to a point where it is blocking the latch before the latch reaches its locking position. That is, the fully inserted IC card would trigger the locking motion of the latch; however, the latch cannot instantly reach the locking position so the user can withdraw the IC card to a blocking position before the latch reaches the locked position.
In a second case, the user is pulling on the IC card with sufficient force against the latch so that when the locking mechanism is triggered to unlock the IC card, the latch is unable to move to the unlocked position. Regarding these situations, it is necessary to continuously drive the solenoid or DC motor until it is determined by sensor feedback that the desired locking state has been achieved. The power and extra sensors required increase the cost and complexity of these mechanisms.